1. Field of the Invention
The present invention relates to a shaft-driven three- or four-wheeled motor vehicle having two rear wheels and a rear fork supporting the rear wheels.
2. Description of the Relevant Art
Three- or four-wheeled motor vehicles having two rear wheels are in use today. Such existing motor vehicles include a swing-arm rear fork supporting the two rear wheels and a shaft-drive mechanism for rotating the rear wheels. The rear fork includes a pair of laterally spaced members, one of which supports a drive shaft extending therethrough, the other member supporting a gear case mounted thereon. In one conventional design, the rear fork member supporting the drive shaft extends back to an axle housing and is integral therewith, and the other rear fork member is shorter with the axle housing coupled thereto. These components are machined and assembled together accurately such that the axis of the axle shaft through the axle housing extends at an angle to the axis of the gear case, and the axis of the pivot of a rear fork lies parallel to the axis of the axle shaft.
One conventional rear wheel support arrangement is disclosed in Japanese Laid-Open Patent Publication No. 59-92280. In the disclosed arrangement an axle housing, one half of one rear fork member, and a gear case are integrally joined in a U-shaped confirguration. The half of one rear fork member, which is laterally spaced from a second rear fork member in which a shaft-drive mechanism is mounted, and the other half of said one rear fork member are coupled end-to-end by axially extending bolts. The gear case and the second rear fork member are similarly coupled together. If there is a positional error or misalignment at the time the gear case and the second rear fork member are assembled together, then the ends of the halves of said one rear fork member are also displaced with respect to each other. Any clearance or displacement resulting from such a positional error is required to be adjusted or eliminated by a shim or the like, a process which makes the assembling procedure tedious and time-consuming.